On the thermo-optical performance of novel photoluminescent components towards an efficient application within urban environments

The application of cool materials (CMs) into the built environment is a widespread solution for mitigating urban overheating. Different types of CMs, e.g. reflective, evaporative, or energy harvesting, have been found to maintain lower superficial temperatures than conventional materials typically used within cities, such as asphalt and concrete. Recently, photoluminescent materials, have been proposed for advanced cooling applications due to their twofold mechanism of rejecting the incident shortwave radiation, also known as Effective Solar Reflectance. In fact, unlike classic reflective CMs, photoluminescent CMs, apart from highly reflecting the incident shortwave radiation, simultaneously emit the absorbed energy at longer wavelengths, contributing to a higher reduction of their surface temperature against bulk colored material. Under this framework, photoluminescent CMs can function at the same time as an energy storage component for lightning applications. This article reports on the in-lab investigation of different photoluminescent components focused on their thermal behavior upon exposure to different realistic boundary conditions. Their thermal performances were evaluated within a climatic chamber configuration with respect to ambient temperature, relative humidity, atmospheric pressure, and incident shortwave radiation. Their profiles are analyzed considering different wave ranges of the spectrum and evaluated accordingly for optimizing their application in the built environment.